Rearrange project writing logic

The WholeProjectDecompiler shall not have too many responsibilities.

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -88,6 +88,7 @@
     <Compile Include="..\ILSpy\DebugInfo\DebugInfoUtils.cs" Link="DebugInfoUtils.cs" />
     <Compile Include="..\ILSpy\DebugInfo\PortableDebugInfoProvider.cs" Link="PortableDebugInfoProvider.cs" />
     <Compile Include="DisassemblerPrettyTestRunner.cs" />
+    <Compile Include="ProjectDecompiler\TargetFrameworkTests.cs" />
     <Compile Include="TestAssemblyResolver.cs" />
     <Compile Include="TestCases\Correctness\StringConcat.cs" />
     <Compile Include="TestCases\ILPretty\Issue1681.cs" />

ICSharpCode.Decompiler.Tests/ProjectDecompiler/TargetFrameworkTests.cs

@@ -0,0 +1,92 @@
+// Copyright (c) 2020 Daniel Grunwald
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
+using NUnit.Framework;
+
+namespace ICSharpCode.Decompiler.Tests
+{
+	[TestFixture]
+	public sealed class TargetFrameworkTests
+	{
+		[TestCase(-1)]
+		[TestCase(0)]
+		[TestCase(1)]
+		[TestCase(99)]
+		[TestCase(int.MinValue)]
+		public void VerifyThrowsForInvalidVersion(int invalidVersion)
+		{
+			// Arrange - nothing
+
+			// Act
+			void CreateInstance() => new TargetFramework(identifier: null, invalidVersion, profile: null);
+
+			// Assert
+			Assert.Throws<ArgumentException>(CreateInstance);
+		}
+
+		[TestCase(100, "v1.0")]
+		[TestCase(102, "v1.0.2")]
+		[TestCase(130, "v1.3")]
+		[TestCase(145, "v1.4.5")]
+		[TestCase(1670, "v16.7")]
+		[TestCase(1800, "v18.0")]
+		public void VerifyVersion(int version, string expectedVersion)
+		{
+			// Arrange - nothing
+
+			// Act
+			var targetFramework = new TargetFramework(identifier: null, version, profile: null);
+
+			// Assert
+			Assert.AreEqual(version, targetFramework.VersionNumber);
+			Assert.AreEqual(expectedVersion, targetFramework.VersionString);
+		}
+
+		[Test]
+		public void VerifyPortableLibrary()
+		{
+			// Arrange
+			const string identifier = ".NETPortable";
+
+			// Act
+			var targetFramework = new TargetFramework(identifier, 100, profile: null);
+
+			// Assert
+			Assert.IsTrue(targetFramework.IsPortableClassLibrary);
+			Assert.AreEqual(identifier, targetFramework.Identifier);
+		}
+
+		[Test]
+		[Pairwise]
+		public void VerifyIdentifierAndProfile(
+			[Values(null, "", ".NETFramework")] string identifier,
+			[Values(null, "", ".Client")] string profile)
+		{
+			// Arrange - nothing
+
+			// Act
+			var targetFramework = new TargetFramework(identifier, 100, profile);
+
+			// Assert
+			Assert.AreEqual(identifier, targetFramework.Identifier);
+			Assert.AreEqual(profile, targetFramework.Profile);
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/IProjectFileWriter.cs

@@ -0,0 +1,41 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Collections.Generic;
+using System.IO;
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
+{
+	/// <summary>
+	/// An interface for a service that creates and writes a project file structure
+	/// for a specific module being decompiled.
+	/// </summary>
+	interface IProjectFileWriter
+	{
+		/// <summary>
+		/// Writes the content of a new project file for the specified <paramref name="module"/> being decompiled.
+		/// </summary>
+		/// <param name="target">The target to write to.</param>
+		/// <param name="project">The information about the project being created.</param>
+		/// <param name="files">A collection of source files to be included into the project, each item is a pair
+		/// of the project entry type and the file path.</param>
+		/// <param name="module">The module being decompiled.</param>
+		void Write(TextWriter target, IProjectInfoProvider project, IEnumerable<(string itemType, string fileName)> files, PEFile module);
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/IProjectInfoProvider.cs

@@ -0,0 +1,49 @@
+// Copyright (c) 2020 Daniel Grunwald
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
+{
+	/// <summary>
+	/// An interface that provides common information for a project being decompiled to.
+	/// </summary>
+	interface IProjectInfoProvider
+	{
+		/// <summary>
+		/// Gets the assembly resolver active for the project.
+		/// </summary>
+		IAssemblyResolver AssemblyResolver { get; }
+
+		/// <summary>
+		/// Gets the C# language version of the project.
+		/// </summary>
+		LanguageVersion LanguageVersion { get; }
+
+		/// <summary>
+		/// Gets the unique ID of the project.
+		/// </summary>
+		Guid ProjectGuid { get; }
+
+		/// <summary>
+		/// Gets the name of the key file being used for strong name signing. Can be null if no file is available.
+		/// </summary>
+		string StrongNameKeyFile { get; }
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/ProjectFileWriterDefault.cs

@@ -0,0 +1,175 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection.PortableExecutable;
+using System.Xml;
+using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.Decompiler.Solution;
+
+namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
+{
+	/// <summary>
+	/// A <see cref="IProjectFileWriter"/> implementation that creates the projects in the default format.
+	/// </summary>
+	sealed class ProjectFileWriterDefault : IProjectFileWriter
+	{
+		/// <summary>
+		/// Creates a new instance of the <see cref="ProjectFileWriterDefault"/> class.
+		/// </summary>
+		/// <returns>A new instance of the <see cref="ProjectFileWriterDefault"/> class.</returns>
+		public static IProjectFileWriter Create() => new ProjectFileWriterDefault();
+
+		/// <inheritdoc />
+		public void Write(
+			TextWriter target,
+			IProjectInfoProvider project,
+			IEnumerable<(string itemType, string fileName)> files,
+			PEFile module)
+		{
+			const string ns = "http://schemas.microsoft.com/developer/msbuild/2003";
+			string platformName = TargetServices.GetPlatformName(module);
+			var targetFramework = TargetServices.DetectTargetFramework(module);
+
+			List<Guid> typeGuids = new List<Guid>();
+			if (targetFramework.IsPortableClassLibrary)
+				typeGuids.Add(ProjectTypeGuids.PortableLibrary);
+			typeGuids.Add(ProjectTypeGuids.CSharpWindows);
+
+			using (XmlTextWriter w = new XmlTextWriter(target)) {
+				w.Formatting = Formatting.Indented;
+				w.WriteStartDocument();
+				w.WriteStartElement("Project", ns);
+				w.WriteAttributeString("ToolsVersion", "4.0");
+				w.WriteAttributeString("DefaultTargets", "Build");
+
+				w.WriteStartElement("PropertyGroup");
+				w.WriteElementString("ProjectGuid", project.ProjectGuid.ToString("B").ToUpperInvariant());
+				w.WriteElementString("ProjectTypeGuids", string.Join(";", typeGuids.Select(g => g.ToString("B").ToUpperInvariant())));
+
+				w.WriteStartElement("Configuration");
+				w.WriteAttributeString("Condition", " '$(Configuration)' == '' ");
+				w.WriteValue("Debug");
+				w.WriteEndElement(); // </Configuration>
+
+				w.WriteStartElement("Platform");
+				w.WriteAttributeString("Condition", " '$(Platform)' == '' ");
+				w.WriteValue(platformName);
+				w.WriteEndElement(); // </Platform>
+
+				if (module.Reader.PEHeaders.IsDll) {
+					w.WriteElementString("OutputType", "Library");
+				} else {
+					switch (module.Reader.PEHeaders.PEHeader.Subsystem) {
+						case Subsystem.WindowsGui:
+							w.WriteElementString("OutputType", "WinExe");
+							break;
+						case Subsystem.WindowsCui:
+							w.WriteElementString("OutputType", "Exe");
+							break;
+						default:
+							w.WriteElementString("OutputType", "Library");
+							break;
+					}
+				}
+
+				w.WriteElementString("LangVersion", project.LanguageVersion.ToString().Replace("CSharp", "").Replace('_', '.'));
+
+				w.WriteElementString("AssemblyName", module.Name);
+				if (targetFramework.Identifier != null)
+					w.WriteElementString("TargetFrameworkIdentifier", targetFramework.Identifier);
+				if (targetFramework.VersionString != null)
+					w.WriteElementString("TargetFrameworkVersion", targetFramework.VersionString);
+				if (targetFramework.Profile != null)
+					w.WriteElementString("TargetFrameworkProfile", targetFramework.Profile);
+				w.WriteElementString("WarningLevel", "4");
+				w.WriteElementString("AllowUnsafeBlocks", "True");
+
+				if (project.StrongNameKeyFile != null) {
+					w.WriteElementString("SignAssembly", "True");
+					w.WriteElementString("AssemblyOriginatorKeyFile", Path.GetFileName(project.StrongNameKeyFile));
+				}
+
+				w.WriteEndElement(); // </PropertyGroup>
+
+				w.WriteStartElement("PropertyGroup"); // platform-specific
+				w.WriteAttributeString("Condition", " '$(Platform)' == '" + platformName + "' ");
+				w.WriteElementString("PlatformTarget", platformName);
+				if (targetFramework.VersionNumber > 400 && platformName == "AnyCPU" && (module.Reader.PEHeaders.CorHeader.Flags & CorFlags.Prefers32Bit) == 0) {
+					w.WriteElementString("Prefer32Bit", "false");
+				}
+				w.WriteEndElement(); // </PropertyGroup> (platform-specific)
+
+				w.WriteStartElement("PropertyGroup"); // Debug
+				w.WriteAttributeString("Condition", " '$(Configuration)' == 'Debug' ");
+				w.WriteElementString("OutputPath", "bin\\Debug\\");
+				w.WriteElementString("DebugSymbols", "true");
+				w.WriteElementString("DebugType", "full");
+				w.WriteElementString("Optimize", "false");
+				w.WriteEndElement(); // </PropertyGroup> (Debug)
+
+				w.WriteStartElement("PropertyGroup"); // Release
+				w.WriteAttributeString("Condition", " '$(Configuration)' == 'Release' ");
+				w.WriteElementString("OutputPath", "bin\\Release\\");
+				w.WriteElementString("DebugSymbols", "true");
+				w.WriteElementString("DebugType", "pdbonly");
+				w.WriteElementString("Optimize", "true");
+				w.WriteEndElement(); // </PropertyGroup> (Release)
+
+
+				w.WriteStartElement("ItemGroup"); // References
+				foreach (var r in module.AssemblyReferences) {
+					if (r.Name != "mscorlib") {
+						w.WriteStartElement("Reference");
+						w.WriteAttributeString("Include", r.Name);
+						var asm = project.AssemblyResolver.Resolve(r);
+						if (asm != null && !project.AssemblyResolver.IsGacAssembly(r)) {
+							w.WriteElementString("HintPath", asm.FileName);
+						}
+						w.WriteEndElement();
+					}
+				}
+				w.WriteEndElement(); // </ItemGroup> (References)
+
+				foreach (IGrouping<string, string> gr in from f in files group f.fileName by f.itemType into g orderby g.Key select g) {
+					w.WriteStartElement("ItemGroup");
+					foreach (string file in gr.OrderBy(f => f, StringComparer.OrdinalIgnoreCase)) {
+						w.WriteStartElement(gr.Key);
+						w.WriteAttributeString("Include", file);
+						w.WriteEndElement();
+					}
+					w.WriteEndElement();
+				}
+				if (targetFramework.IsPortableClassLibrary) {
+					w.WriteStartElement("Import");
+					w.WriteAttributeString("Project", "$(MSBuildExtensionsPath32)\\Microsoft\\Portable\\$(TargetFrameworkVersion)\\Microsoft.Portable.CSharp.targets");
+					w.WriteEndElement();
+				} else {
+					w.WriteStartElement("Import");
+					w.WriteAttributeString("Project", "$(MSBuildToolsPath)\\Microsoft.CSharp.targets");
+					w.WriteEndElement();
+				}
+
+				w.WriteEndDocument();
+			}
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/TargetFramework.cs

@@ -0,0 +1,94 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Text;
+
+namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
+{
+	/// <summary>
+	/// A class describing the target framework of a module.
+	/// </summary>
+	sealed class TargetFramework
+	{
+		const string DotNetPortableIdentifier = ".NETPortable";
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="TargetFramework"/> class.
+		/// </summary>
+		/// <param name="identifier">The framework identifier string. Can be null.</param>
+		/// <param name="version">The framework version string. Must be greater than 100 (where 100 corresponds to v1.0).</param>
+		/// <param name="profile">The framework profile. Can be null.</param>
+		public TargetFramework(string identifier, int version, string profile)
+		{
+			if (version < 100) {
+				throw new ArgumentException("The version number must be greater than or equal to 100", nameof(version));
+			}
+
+			Identifier = identifier;
+			VersionNumber = version;
+			VersionString = "v" + GetVersionString(version);
+			Profile = profile;
+			IsPortableClassLibrary = identifier == DotNetPortableIdentifier;
+		}
+
+		/// <summary>
+		/// Gets the target framework identifier. Can be null if not defined.
+		/// </summary>
+		public string Identifier { get; }
+		
+		/// <summary>
+		/// Gets the target framework version, e.g. "v4.5".
+		/// </summary>
+		public string VersionString { get; }
+
+		/// <summary>
+		/// Gets the target framework version as integer (multiplied by 100), e.g. 450.
+		/// </summary>
+		public int VersionNumber { get; }
+
+		/// <summary>
+		/// Gets the target framework profile. Can be null if not set or not available.
+		/// </summary>
+		public string Profile { get; }
+
+		/// <summary>
+		/// Gets a value indicating whether the target is a portable class library (PCL).
+		/// </summary>
+		public bool IsPortableClassLibrary { get; }
+
+		static string GetVersionString(int version)
+		{
+			int major = version / 100;
+			int minor = version % 100 / 10;
+			int patch = version % 10;
+
+			var versionBuilder = new StringBuilder(8);
+			versionBuilder.Append(major);
+			versionBuilder.Append('.');
+			versionBuilder.Append(minor);
+
+			if (patch != 0) {
+				versionBuilder.Append('.');
+				versionBuilder.Append(patch);
+			}
+
+			return versionBuilder.ToString();
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/TargetServices.cs

@@ -0,0 +1,129 @@
+// Copyright (c) 2020 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Linq;
+using System.Reflection.PortableExecutable;
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
+{
+	/// <summary>
+	/// Helper services for determining the target framework and platform of a module.
+	/// </summary>
+	static class TargetServices
+	{
+		const string VersionToken = "Version=";
+		const string ProfileToken = "Profile=";
+
+		/// <summary>
+		/// Gets the <see cref="TargetFramework"/> for the specified <paramref name="module"/>.
+		/// </summary>
+		/// <param name="module">The module to get the target framework description for. Cannot be null.</param>
+		/// <returns>A new instance of the <see cref="TargetFramework"/> class that describes the specified <paramref name="module"/>.
+		/// </returns>
+		public static TargetFramework DetectTargetFramework(PEFile module)
+		{
+			if (module is null) {
+				throw new ArgumentNullException(nameof(module));
+			}
+
+			int versionNumber;
+			switch (module.GetRuntime()) {
+				case TargetRuntime.Net_1_0:
+					versionNumber = 100;
+					break;
+
+				case TargetRuntime.Net_1_1:
+					versionNumber = 110;
+					break;
+
+				case TargetRuntime.Net_2_0:
+					versionNumber = 200;
+					// TODO: Detect when .NET 3.0/3.5 is required
+					break;
+
+				default:
+					versionNumber = 400;
+					break;
+			}
+
+			string targetFrameworkIdentifier = null;
+			string targetFrameworkProfile = null;
+
+			string targetFramework = module.DetectTargetFrameworkId();
+			if (!string.IsNullOrEmpty(targetFramework)) {
+				string[] frameworkParts = targetFramework.Split(',');
+				targetFrameworkIdentifier = frameworkParts.FirstOrDefault(a => !a.StartsWith(VersionToken, StringComparison.OrdinalIgnoreCase) && !a.StartsWith(ProfileToken, StringComparison.OrdinalIgnoreCase));
+				string frameworkVersion = frameworkParts.FirstOrDefault(a => a.StartsWith(VersionToken, StringComparison.OrdinalIgnoreCase));
+
+				if (frameworkVersion != null) {
+					versionNumber = int.Parse(frameworkVersion.Substring(VersionToken.Length + 1).Replace(".", ""));
+					if (versionNumber < 100) versionNumber *= 10;
+				}
+
+				string frameworkProfile = frameworkParts.FirstOrDefault(a => a.StartsWith(ProfileToken, StringComparison.OrdinalIgnoreCase));
+				if (frameworkProfile != null)
+					targetFrameworkProfile = frameworkProfile.Substring(ProfileToken.Length);
+			}
+
+			return new TargetFramework(targetFrameworkIdentifier, versionNumber, targetFrameworkProfile);
+		}
+
+		/// <summary>
+		/// Gets the string representation (name) of the target platform of the specified <paramref name="module"/>.
+		/// </summary>
+		/// <param name="module">The module to get the target framework description for. Cannot be null.</param>
+		/// <returns>The platform name, e.g. "AnyCPU" or "x86".</returns>
+		public static string GetPlatformName(PEFile module)
+		{
+			if (module is null) {
+				throw new ArgumentNullException(nameof(module));
+			}
+
+			var headers = module.Reader.PEHeaders;
+			var architecture = headers.CoffHeader.Machine;
+			var characteristics = headers.CoffHeader.Characteristics;
+			var corflags = headers.CorHeader.Flags;
+
+			switch (architecture) {
+				case Machine.I386:
+					if ((corflags & CorFlags.Prefers32Bit) != 0)
+						return "AnyCPU";
+
+					if ((corflags & CorFlags.Requires32Bit) != 0)
+						return "x86";
+
+					// According to ECMA-335, II.25.3.3.1 CorFlags.Requires32Bit and Characteristics.Bit32Machine must be in sync
+					// for assemblies containing managed code. However, this is not true for C++/CLI assemblies.
+					if ((corflags & CorFlags.ILOnly) == 0 && (characteristics & Characteristics.Bit32Machine) != 0)
+						return "x86";
+					return "AnyCPU";
+
+				case Machine.Amd64:
+					return "x64";
+
+				case Machine.IA64:
+					return "Itanium";
+
+				default:
+					return architecture.ToString();
+			}
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -21,7 +21,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
-using System.Xml;
 using ICSharpCode.Decompiler.CSharp.OutputVisitor;
 using ICSharpCode.Decompiler.CSharp.Syntax;
 using ICSharpCode.Decompiler.CSharp.Transforms;
@@ -29,9 +28,7 @@ using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.Util;
 using System.Threading;
 using System.Text;
-using System.Reflection.PortableExecutable;
 using System.Reflection.Metadata;
-using static ICSharpCode.Decompiler.Metadata.DotNetCorePathFinderExtensions;
 using static ICSharpCode.Decompiler.Metadata.MetadataExtensions;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.Solution;
@@ -42,7 +39,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 	/// <summary>
 	/// Decompiles an assembly into a visual studio project file.
 	/// </summary>
-	public class WholeProjectDecompiler
+	public class WholeProjectDecompiler : IProjectInfoProvider
 	{
 		#region Settings
 		/// <summary>
@@ -106,6 +103,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			ProjectGuid = projectGuid;
 			AssemblyResolver = assemblyResolver ?? throw new ArgumentNullException(nameof(assemblyResolver));
 			DebugInfoProvider = debugInfoProvider;
+			projectWriter = ProjectFileWriterDefault.Create();
 		}
 
 		// per-run members
@@ -120,6 +118,8 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		/// </remarks>
 		protected string targetDirectory;
 
+		readonly IProjectFileWriter projectWriter;
+
 		public void DecompileProject(PEFile moduleDefinition, string targetDirectory, CancellationToken cancellationToken = default(CancellationToken))
 		{
 			string projectFileName = Path.Combine(targetDirectory, CleanUpFileName(moduleDefinition.Name) + ".csproj");
@@ -140,197 +140,13 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			if (StrongNameKeyFile != null) {
 				File.Copy(StrongNameKeyFile, Path.Combine(targetDirectory, Path.GetFileName(StrongNameKeyFile)));
 			}
-			return WriteProjectFile(projectFileWriter, files, moduleDefinition);
-		}
-
-		#region WriteProjectFile
-		ProjectId WriteProjectFile(TextWriter writer, IEnumerable<(string itemType, string fileName)> files, Metadata.PEFile module)
-		{
-			const string ns = "http://schemas.microsoft.com/developer/msbuild/2003";
-			string platformName = GetPlatformName(module);
-			Guid guid = this.ProjectGuid;
-			var targetFramework = DetectTargetFramework(module);
-
-			List<Guid> typeGuids = new List<Guid>();
-			if (targetFramework.IsPortableClassLibrary)
-				typeGuids.Add(ProjectTypeGuids.PortableLibrary);
-			typeGuids.Add(ProjectTypeGuids.CSharpWindows);
-			// TODO: .NET core support
-
-			using (XmlTextWriter w = new XmlTextWriter(writer)) {
-				w.Formatting = Formatting.Indented;
-				w.WriteStartDocument();
-				w.WriteStartElement("Project", ns);
-				w.WriteAttributeString("ToolsVersion", "4.0");
-				w.WriteAttributeString("DefaultTargets", "Build");
-
-				w.WriteStartElement("PropertyGroup");
-				w.WriteElementString("ProjectGuid", guid.ToString("B").ToUpperInvariant());
-				w.WriteElementString("ProjectTypeGuids", string.Join(";", typeGuids.Select(g => g.ToString("B").ToUpperInvariant())));
-
-				w.WriteStartElement("Configuration");
-				w.WriteAttributeString("Condition", " '$(Configuration)' == '' ");
-				w.WriteValue("Debug");
-				w.WriteEndElement(); // </Configuration>
-
-				w.WriteStartElement("Platform");
-				w.WriteAttributeString("Condition", " '$(Platform)' == '' ");
-				w.WriteValue(platformName);
-				w.WriteEndElement(); // </Platform>
-
-				if (module.Reader.PEHeaders.IsDll) {
-					w.WriteElementString("OutputType", "Library");
-				} else {
-					switch (module.Reader.PEHeaders.PEHeader.Subsystem) {
-						case Subsystem.WindowsGui:
-							w.WriteElementString("OutputType", "WinExe");
-							break;
-						case Subsystem.WindowsCui:
-							w.WriteElementString("OutputType", "Exe");
-							break;
-						default:
-							w.WriteElementString("OutputType", "Library");
-							break;
-					}
-				}
-
-				w.WriteElementString("LangVersion", LanguageVersion.ToString().Replace("CSharp", "").Replace('_', '.'));
-
-				w.WriteElementString("AssemblyName", module.Name);
-				if (targetFramework.TargetFrameworkIdentifier != null)
-					w.WriteElementString("TargetFrameworkIdentifier", targetFramework.TargetFrameworkIdentifier);
-				if (targetFramework.TargetFrameworkVersion != null)
-					w.WriteElementString("TargetFrameworkVersion", targetFramework.TargetFrameworkVersion);
-				if (targetFramework.TargetFrameworkProfile != null)
-					w.WriteElementString("TargetFrameworkProfile", targetFramework.TargetFrameworkProfile);
-				w.WriteElementString("WarningLevel", "4");
-				w.WriteElementString("AllowUnsafeBlocks", "True");
-
-				if (StrongNameKeyFile != null) {
-					w.WriteElementString("SignAssembly", "True");
-					w.WriteElementString("AssemblyOriginatorKeyFile", Path.GetFileName(StrongNameKeyFile));
-				}
 
-				w.WriteEndElement(); // </PropertyGroup>
-
-				w.WriteStartElement("PropertyGroup"); // platform-specific
-				w.WriteAttributeString("Condition", " '$(Platform)' == '" + platformName + "' ");
-				w.WriteElementString("PlatformTarget", platformName);
-				if (targetFramework.VersionNumber > 400 && platformName == "AnyCPU" && (module.Reader.PEHeaders.CorHeader.Flags & CorFlags.Prefers32Bit) == 0) {
-					w.WriteElementString("Prefer32Bit", "false");
-				}
-				w.WriteEndElement(); // </PropertyGroup> (platform-specific)
-
-				w.WriteStartElement("PropertyGroup"); // Debug
-				w.WriteAttributeString("Condition", " '$(Configuration)' == 'Debug' ");
-				w.WriteElementString("OutputPath", "bin\\Debug\\");
-				w.WriteElementString("DebugSymbols", "true");
-				w.WriteElementString("DebugType", "full");
-				w.WriteElementString("Optimize", "false");
-				w.WriteEndElement(); // </PropertyGroup> (Debug)
-
-				w.WriteStartElement("PropertyGroup"); // Release
-				w.WriteAttributeString("Condition", " '$(Configuration)' == 'Release' ");
-				w.WriteElementString("OutputPath", "bin\\Release\\");
-				w.WriteElementString("DebugSymbols", "true");
-				w.WriteElementString("DebugType", "pdbonly");
-				w.WriteElementString("Optimize", "true");
-				w.WriteEndElement(); // </PropertyGroup> (Release)
-
-
-				w.WriteStartElement("ItemGroup"); // References
-				foreach (var r in module.AssemblyReferences) {
-					if (r.Name != "mscorlib") {
-						w.WriteStartElement("Reference");
-						w.WriteAttributeString("Include", r.Name);
-						var asm = AssemblyResolver.Resolve(r);
-						if (!AssemblyResolver.IsGacAssembly(r)) {
-							if (asm != null) {
-								w.WriteElementString("HintPath", asm.FileName);
-							}
-						}
-						w.WriteEndElement();
-					}
-				}
-				w.WriteEndElement(); // </ItemGroup> (References)
-
-				foreach (IGrouping<string, string> gr in (from f in files group f.fileName by f.itemType into g orderby g.Key select g)) {
-					w.WriteStartElement("ItemGroup");
-					foreach (string file in gr.OrderBy(f => f, StringComparer.OrdinalIgnoreCase)) {
-						w.WriteStartElement(gr.Key);
-						w.WriteAttributeString("Include", file);
-						w.WriteEndElement();
-					}
-					w.WriteEndElement();
-				}
-				if (targetFramework.IsPortableClassLibrary) {
-					w.WriteStartElement("Import");
-					w.WriteAttributeString("Project", "$(MSBuildExtensionsPath32)\\Microsoft\\Portable\\$(TargetFrameworkVersion)\\Microsoft.Portable.CSharp.targets");
-					w.WriteEndElement();
-				} else {
-					w.WriteStartElement("Import");
-					w.WriteAttributeString("Project", "$(MSBuildToolsPath)\\Microsoft.CSharp.targets");
-					w.WriteEndElement();
-				}
-
-				w.WriteEndDocument();
-			}
-
-			return new ProjectId(platformName, guid, ProjectTypeGuids.CSharpWindows);
+			projectWriter.Write(projectFileWriter, this, files, moduleDefinition);
+			
+			string platformName = TargetServices.GetPlatformName(moduleDefinition);
+			return new ProjectId(platformName, ProjectGuid, ProjectTypeGuids.CSharpWindows);
 		}
 
-		struct TargetFramework
-		{
-			public string TargetFrameworkIdentifier;
-			public string TargetFrameworkVersion;
-			public string TargetFrameworkProfile;
-			public int VersionNumber;
-			public bool IsPortableClassLibrary => TargetFrameworkIdentifier == ".NETPortable";
-		}
-
-		private TargetFramework DetectTargetFramework(PEFile module)
-		{
-			TargetFramework result = default;
-
-			switch (module.GetRuntime()) {
-				case Metadata.TargetRuntime.Net_1_0:
-					result.VersionNumber = 100;
-					result.TargetFrameworkVersion = "v1.0";
-					break;
-				case Metadata.TargetRuntime.Net_1_1:
-					result.VersionNumber = 110;
-					result.TargetFrameworkVersion = "v1.1";
-					break;
-				case Metadata.TargetRuntime.Net_2_0:
-					result.VersionNumber = 200;
-					result.TargetFrameworkVersion = "v2.0";
-					// TODO: Detect when .NET 3.0/3.5 is required
-					break;
-				default:
-					result.VersionNumber = 400;
-					result.TargetFrameworkVersion = "v4.0";
-					break;
-			}
-
-			string targetFramework = module.DetectTargetFrameworkId();
-			if (!string.IsNullOrEmpty(targetFramework)) {
-				string[] frameworkParts = targetFramework.Split(',');
-				result.TargetFrameworkIdentifier = frameworkParts.FirstOrDefault(a => !a.StartsWith("Version=", StringComparison.OrdinalIgnoreCase) && !a.StartsWith("Profile=", StringComparison.OrdinalIgnoreCase));
-				string frameworkVersion = frameworkParts.FirstOrDefault(a => a.StartsWith("Version=", StringComparison.OrdinalIgnoreCase));
-				if (frameworkVersion != null) {
-					result.TargetFrameworkVersion = frameworkVersion.Substring("Version=".Length);
-					result.VersionNumber = int.Parse(frameworkVersion.Substring("Version=v".Length).Replace(".", ""));
-					if (result.VersionNumber < 100) result.VersionNumber *= 10;
-				}
-				string frameworkProfile = frameworkParts.FirstOrDefault(a => a.StartsWith("Profile=", StringComparison.OrdinalIgnoreCase));
-				if (frameworkProfile != null)
-					result.TargetFrameworkProfile = frameworkProfile.Substring("Profile=".Length);
-			}
-			return result;
-		}
-
-		#endregion
-
 		#region WriteCodeFilesInProject
 		protected virtual bool IncludeTypeWhenDecompilingProject(PEFile module, TypeDefinitionHandle type)
 		{
@@ -571,32 +387,6 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 					return false;
 			}
 		}
-
-		public static string GetPlatformName(Metadata.PEFile module)
-		{
-			var headers = module.Reader.PEHeaders;
-			var architecture = headers.CoffHeader.Machine;
-			var characteristics = headers.CoffHeader.Characteristics;
-			var corflags = headers.CorHeader.Flags;
-			switch (architecture) {
-				case Machine.I386:
-					if ((corflags & CorFlags.Prefers32Bit) != 0)
-						return "AnyCPU";
-					if ((corflags & CorFlags.Requires32Bit) != 0)
-						return "x86";
-					// According to ECMA-335, II.25.3.3.1 CorFlags.Requires32Bit and Characteristics.Bit32Machine must be in sync
-					// for assemblies containing managed code. However, this is not true for C++/CLI assemblies.
-					if ((corflags & CorFlags.ILOnly) == 0 && (characteristics & Characteristics.Bit32Machine) != 0)
-						return "x86";
-					return "AnyCPU";
-				case Machine.Amd64:
-					return "x64";
-				case Machine.IA64:
-					return "Itanium";
-				default:
-					return architecture.ToString();
-			}
-		}
 	}
 
 	public readonly struct DecompilationProgress

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -61,9 +61,14 @@
     <Compile Include="CSharp\Annotations.cs" />
     <Compile Include="CSharp\CallBuilder.cs" />
     <Compile Include="CSharp\CSharpLanguageVersion.cs" />
+    <Compile Include="CSharp\ProjectDecompiler\IProjectFileWriter.cs" />
     <Compile Include="CSharp\OutputVisitor\GenericGrammarAmbiguityVisitor.cs" />
+    <Compile Include="CSharp\ProjectDecompiler\IProjectInfoProvider.cs" />
+    <Compile Include="CSharp\ProjectDecompiler\ProjectFileWriterDefault.cs" />
     <Compile Include="CSharp\RequiredNamespaceCollector.cs" />
     <Compile Include="CSharp\SequencePointBuilder.cs" />
+    <Compile Include="CSharp\ProjectDecompiler\TargetFramework.cs" />
+    <Compile Include="CSharp\ProjectDecompiler\TargetServices.cs" />
     <Compile Include="IL\Transforms\IndexRangeTransform.cs" />
     <Compile Include="CSharp\TranslatedStatement.cs" />
     <Compile Include="DebugInfo\KnownGuids.cs" />